The present invention relates to a method of producing a hydrogen-rich gas with a hydrogen content of at least 85 volume percent.
More particularly, it relates to a method of producing a hydrogen-rich gas by gasification (partial oxidation) of finely granular to pulverulent fuels at temperatures above the slag melting point, wherein the produced partial oxidation crude gas is indirectly cooled with steam generation in a waste heat boiler located after the gasifier and is subjected then to a de-dusting, a catalytic CO-conversion and a desulfurization and CO.sub.2 removal.
The partial oxidation crude gas produced during gasification of finely granular to pulverulent fuels has, depending on the composition of the used fuel and the reaction conditions of the gasification, a ratio of carbon monoxide to hydrogen which can be in the region between 1:1 to 2.7:1. For producing a hydrogen-rich gas which for example must be used for synthesis of ammonia or for hydrating of organic compounds, it is however required that the ratio of carbon monoxide to hydrogen be lowered to the value under 0.1. For obtaining these values the excessive CO must be converted into hydrogen in accordance with the CO-conversion reaction EQU CO+H.sub.2 O.fwdarw.H.sub.2 +CO.sub.2
Methods for producing a hydrogen-rich gas of the above mentioned general type are known. When the catalyst used for the catalytic conversion reaction is not sulfur resistant, the desulfurization of the gas is often performed before the conversion and not after. For the conversion itself, it is required that the gas to be converted be loaded with water vapor before entering the conversion reactor, and after the conversion cleaned from the excessive vapor again. For this purpose so-called moisturizing-demoisturizing systems are known. During the utilization of sulfur resistant conversion catalysts, the loading of the partial oxidation gas with water vapor can be performed however in such a manner that it is directly injected into the hot gas before the de-dusting, and after the conversion the excessive vapor is again condensed from the gas. A condensate return in the hot partial oxidation crude gas is however possible only to a limited extent when the gas must be de-dusted in a dry process. Depending on the utilized methods for moisturizing and de-moisturizing of the gas, in each case significant heat quantities in low temperature region are withdrawn with the excessive vapor condensate. Simultaneously, the intensive heat exchange for heating of the gas and the condensation of the excessive vapor require high apparatus expenses.